[HN Gopher] Hacking an old Kindle to display bus arrival times
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Hacking an old Kindle to display bus arrival times
Author : mengchengfeng
Score : 117 points
Date : 2026-02-24 19:43 UTC (3 hours ago)
(HTM) web link (www.mariannefeng.com)
(TXT) w3m dump (www.mariannefeng.com)
| michaelbuckbee wrote:
| I love using Kindle's as single purpose
| tablet/interfaces/displays. I'm the weirdo who actually prefers
| the LCD displays vs eInk and it's incredibly easy to set Kindle
| Fire's into dev mode which lets you display a webpage, never turn
| off while connected to power and never show ads.
|
| You can regularly find the Kindle Fire HD10s for ~$40
| mengchengfeng wrote:
| Good to know about Kindle Fire. And hah, I can totally see why
| you'd prefer LCD's over e-ink - no ghosting + readable in pitch
| dark would be a sweet upgrade to the dashboard.
| SirFatty wrote:
| For some reason, this project reminds me of this one:
|
| https://engineersneedart.com/systemsix/systemsix.html
| mengchengfeng wrote:
| Woah this is really cool! Makes me want to create a custom
| mount
| FlyingSnake wrote:
| Kindles are fun devices to hack and play with. I can grab an old
| kindle for EUR15-20 on eBay.
|
| I did the same last year and had lots of fun in the process.
|
| https://samkhawase.com/blog/hacking-kindle/
| mengchengfeng wrote:
| I love it! Always fun to see the route somebody else took to
| get to the same end product.
|
| Your post is making me want to try more Cloudflare Developer
| Platform stuff like Cloudflare Workers.
| moffkalast wrote:
| For the less reverse-engineering prone among us, there are also
| similarly sized e-ink displays that plug into Raspberry Pi DSI
| ports for maybe $5 more on Aliexpress. They might actually be
| salvaged kindle screens.
| slig wrote:
| Do you have a model number or link, please?
| uyzstvqs wrote:
| Can you start jailbreaking straight away, or does it require an
| internet connection and Amazon account first during setup?
| mkmk wrote:
| I was glad to see the note about battery life down at the bottom.
| My biggest challenge with the old Kindles I have laying around is
| that most of them won't hold a charge!
| mengchengfeng wrote:
| Yeah that was definitely a worry of mine before I booted it up.
| Luckily it's still got decent battery life. We'll see how it
| holds up in 6 months...
|
| Dyson vacuums and Kindles are not the same whatsoever, but I
| wonder how easily it'd be to swap out the battery on an older
| Kindle. For our vacuum, all I needed was a 20 dollar
| replacement battery and the will unscrew 3 mini screws.
| bpmct wrote:
| I haven't developed on the Kindle ecosystem, but with old Nook
| devices I am able to set a screensaver, alarm, and put the
| device into deep sleep between refreshes. This changed my
| battery life from ~48 hours into 30+ days of battery life even
| with some old devices.
|
| The "electric sign" app does this, which is where I referenced
| the code.
|
| With trmnl, the image only refreshes every 10 mins so the
| device will set a ~9 minute alarm to wake the device right
| before it needs to load the next update.
|
| The refresh period is also configurable so a slower refresh
| interval (e.g. every hour for less time-sensitive screens)
| yields larger battery savings
| BobaFloutist wrote:
| One thing that's disappointed me is that despite all the
| excitement over better and cheaper battery technology, you
| can't buy a cheapish drop in replacement battery for e.g. an
| old kindle that has more storage capacity than the OEM version.
|
| I understand there's like all sorts of complexities in
| standards, form factors, voltage, wattage, etc, but I really
| wish I could upgrade my old devices like that.
| adhamsalama wrote:
| Why Jailbreak the Kindle when you can just open its browser and
| visit a website that shows the arrival times?
|
| The Kindle browser is surprisingly decent, I made Claude Code
| generate an RSS feed reader compatible with the Kindle browser,
| with the ability to read full articles (for those feeds that
| require you to visit the website), and download articles. It also
| supports Reddit and Google News RSS feed. This is my new favorite
| way of browsing the internet.
|
| https://github.com/adhamsalama/simple-rss-reader
| mengchengfeng wrote:
| It's easier to load up a page in the Kindle browser, but more
| fun to jailbreak :D
|
| I also didn't want the browser bar at the top.
| adhamsalama wrote:
| Fair enough. I did consider jailbreaking my Kindle but I am
| afraid of bricking it.
| mengchengfeng wrote:
| Also fair - bricking it was definitely one of my main
| concerns.
|
| After going through this process though, I'd say as long as
| somebody has basic linux knowledge, chances of bricking are
| pretty low.
| TZubiri wrote:
| A little bit of a hijack, but it's hard to find a more relevant
| time to post this.
|
| For a defunct startup, I built this exact thing as a product for
| coffee shops:
|
| cafetren.com.ar
|
| https://cafetren-com-ar.translate.goog/?_x_tr_sl=auto&_x_tr_...
| (translated from spanish):
| hex4def6 wrote:
| As someone who worked on kindle power consumption many years ago:
| One of the (by far) biggest consumers of power is the WiFi
| connection. It has to wake up and respond to the AP in order to
| not get disconnected every x seconds.
|
| Off the top of my head, I think 'on' average power consumption
| was ~700uA without wifi, and about 1.5mA+/- with Wifi. This is
| from over a decade ago, so my memory is fuzzy though...
|
| Obviously, page changes used relatively large amounts of power. I
| don't recall the exact amounts, but it was 100s of mA for
| seconds.
|
| There is also an "every x pages, do a full screen refresh (black
| to white)" to fix up the ghosting issue that the article writer
| saw.
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(page generated 2026-02-24 23:00 UTC)